Easy Red Lentil Soup with Lemon

This lemony red lentil soup recipe takes plain lentils to the next level. Make it once, and you’ll be hooked!

Red lentil soup is good on its own, but cooking the tomatoes correctly and adding fresh lemon juice at the end takes it from “this is good soup,” to “Wow, this soup is amazing!”

In fact, adding fresh lemon juice (or any acid) at the end of the cooking process is a secret chef’s trick that makes any soup recipe better.

Plus, it’s easy! The flavor of the onion, tomatoes, and spices is wonderful. I added the grated carrot because I had some carrots we needed to use, which turned out amazing.

This soup is not only delicious but uber nutritious, too. Lentils have a whopping 24 grams of protein per 1 cup cooked, 8 grams of fiber, and 0 sugar. If you’re interested, I go into detail about why protein and fiber are the keys to optimal health here.

Traditional red lentil soup with lemon is super easy to make; the key to getting it right is in the cooking process and following the steps exactly as written.

Ingredients

• extra virgin olive oil
• 1 white or yellow onion
• 1-2 medium carrots
• 2 Roma tomatoes or grape tomatoes (any tomatoes can work)
• 2 fresh garlic cloves
• ground cumin
• chicken stock or veggie stock (homemade or store-bought; water can work, too)
• red lentils
• 1-2 fresh lemons (zest and juice)
• salt & pepper

To Garnish

• fresh cilantro (or other fresh herbs like parsley or chives if you don’t like cilantro)
• whole cumin seeds; dry toasted or toasted in a little ghee
• a drizzle of extra virgin olive oil

All of the garnishes are optional and recommended 😉

See the recipe card below for details and instructions, and you can join me in my kitchen to watch the full lentil soup tutorial here on my YouTube Channel:

How to Make Red Lentil Soup

1. Heat the olive oil in a large pot, then cook the onions, carrot & tomatoes until the oil takes on the red color of the tomatoes.
2. Add in the garlic and cumin and cook for a few minutes until the garlic is fragrant.
3. Quickly rinse the lentils (I’ve forgotten to do this and it’s OK), then add them with the liquid and salt to the pot.
4. Simmer for 30 minutes until the lentils are soft. No need to blend as red lentils break down pretty easily. Although, you can blend it with an immersion blender if you’d like.
5. Turn off the heat and stir in the lemon zest and juice.
6. Garnish as desired and enjoy!

Key Tips to Get It Right

Here are the key steps to making red lentil soup just right.

1. Cook the tomatoes with the sauteed onion until the oil takes on the red color of the tomatoes. Fresh tomatoes are perfect here, finely chop them and use the juices and all. My fiance usually uses Roma tomatoes, but I’ve also used grape tomatoes and vine tomatoes. If the tomatoes don’t look great at your store, 1 cup of crushed plain tomatoes from a can will work, too.
2. The fresh lemon really makes the dish, so don’t skip it. Always use fresh lemon juice.
3. Toast whole cumin seeds to garnish the soup. You can dry-toast the cumin seeds or toast them in ghee, both are great options. You can skip this step if you don’t have whole cumin seeds, but I highly recommend trying it—it’s wonderful!

Lentil soup is great any time of year, but it’s especially good in the cooler months. It’s similar to my easy lentil soup recipe, which is a base lentil soup recipe that you can use any lentils to make.

Substitutions & Variations

This recipe is perfect as written, but you can change it up if necessary.

• Lentils – Red lentils generally cook faster than green or black lentils. If you use another type of lentil here, simmer the soup until the lentils are soft, up to 2 hours. You may also need to add more liquid if you simmer it longer. You don’t need to soak lentils, but it’s a good idea to quickly rinse them (see FAQs below for more).
• Carrot – Carrots are optional and a great way to get more veggies into your food. I like to freshly grate it on a box grater. You can also dice or mince it. I would avoid pre-shredded carrots because they’re dehydrated and the texture isn’t great. You can leave out the carrot entirely if that works better for you.
• Liquid – You need 6 cups of the liquid total to make this soup. You can use any stock you have on hand to make lentil soup. You can also use all water if that’s what you have. I generally use 4 cups of homemade vegetable stock or chicken stock (homemade or store-bought) plus 2 cups of water. The last time I bought veggie stock in a box I didn’t love it, but the “Better Than Bullion” brand veggie base is actually pretty good! You can find it at most stores and they don’t add a bunch of unhealthy ingredients. You simply combine it with hot water to make veggies stock; use it according to the instructions on the jar.
• Spicy – If you want a spicy soup, go ahead and add a minced jalapeno or Fresno pepper to the onion and tomato mixture. Cooking peppers in oil make your whole dish spicy.
• Dietary – This red lentil soup is already gluten-free and dairy-free. Make it vegan by using water or veggie stock instead of chicken stock. If you make the toasted cumin seeds, ghee is dairy-free but not vegan, so use olive oil instead.

Equipment

Pot: If you make soup a lot, a Dutch oven is a worthy investment. I am a sucker for the traditional French brand Le Creuset, but I just found this super affordable Dutch oven on Amazon so if you’re in the market for one it’s a great option.

I like to make healthy soup recipes in a 6-quart Dutch oven so I can leave it on warm on the stove for a few hours or all afternoon. If you use a Dutch oven, let the soup come to room temp then simply put the lid on and move the Dutch oven to the fridge. You can heat the whole thing back up on the stove or portion out what you want. You can leave the Dutch oven with food in it in the fridge up to 3 days. It’s not airtight, so move it to a storage container if keeping longer.

You can also make this in any large pot you have.

What about an Instant Pot? To be honest, it’s not worth it to make red lentil soup in an Instant Pot or pressure cooker. It only takes 30 minutes to simmer red lentils on the stove. By the time a pressure cooker comes up to pressure and releases, you’ll barely have saved time, and you risk overcooking the lentils into a mush mess.

Storage

Let the soup come to room temperature, then store it in the fridge.

Lentil soup leftovers are kept in the refrigerator for up to 5 days in an airtight container. After that, freeze it for up to 3 months.

Find more lentil recipes here.

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Description

This traditional red lentil soup recipe with lemon is the best lentil soup we’ve ever tried! It’s full of nutrients, fiber, protein, and hydration. You’ll want to make it over and over again.

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• 2 tablespoons extra virgin olive oil, plus more to drizzle
• 1 yellow onion, diced
• 2 medium carrots, grated on a box grater (about 1 cup)
• 2 Roma tomatoes, finely chopped including the juices (or 10–12 grape tomatoes, whatever looks good)
• 2 garlic cloves, minced or grated
• 1.5 teaspoons ground cumin
• 1.5 cups red lentils
• 4 cups (1-quart) chicken stock or veggie stock (or bone broth for more protein)
• 2 cups of water
• 2 teaspoons sea salt, more or less to taste (3+ teaspoons if your stock is low-sodium)
• a few spins of freshly ground black pepper
• 1 teaspoon lemon zest
• 3 tablespoons fresh lemon juice (from 1 large or 2 small lemons; zest it first)
• garnish: whole cumin seeds dry-toasted or toasted in ghee*, a drizzle of extra virgin olive oil, freshly chopped cilantro (or parsley or chives if you don’t like cilantro)

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1. Preheat a large soup pot or Dutch oven over medium-high heat. Add the olive oil and let it heat up for 30 seconds. Add the onion, carrot & tomatoes (including any juices of the tomatoes); sauté 7-10 minutes until the veggies are soft and the oil has taken on the red color of the tomatoes. It’s important the tomatoes are fully cooked before adding the lentils—you’ll know they’re done when the oil is slightly red.
2. Turn the heat to medium and add the garlic, cumin, a few spins of freshly cracked black pepper, and a teaspoon of sea salt. Cook 1-2 minutes until very fragrant, being careful not to burn the garlic.
3. While the onions and tomatoes cook, rinse the lentils in a strainer or colander under cool water for 30-60 seconds.
4. Add the lentils to the pot and give them a quick stir into the oil, then add the stock and water (6 cups of liquid total). Add another teaspoon of sea salt and bring to a rolling simmer, then reduce to a gentle simmer. Simmer for 30-40 minutes until the red lentils are very soft. No need to puree; red lentils break down as they cook.
5. Turn off the heat and stir in 1 teaspoon of lemon zest and 3 tablespoons of fresh lemon juice. The lemon is key, don’t skip it. Always add lemon juice off the heat. Adjust salt and pepper to taste.
6. To serve, garnish with a drizzle of olive oil and freshly chopped cilantro or chives, and a few pinches of the toasted whole cumin seeds, if desired. Keeps in the fridge, covered, for up to 5 days. Freezes well ungarnished.

*To toast the cumin seeds, heat a small skillet or frying pan over medium-high heat then add 1-2 teaspoons of dry whole cumin seeds. Toast them dry for about 4-5 minutes until very fragrant. If it’s popping loudly or smoking the pan is too hot. The cumin seeds should be lightly toasted in 4-5 minutes. Move them to a plate or bowl to cool for a few minutes. They’re great dry-toasted, and you can elevate them even more by adding an equal amount of ghee (clarified butter) to the pan after 1 minute of dry toasting. This will lightly fry the seeds in the ghee and give you a wonderful soup garnish. 

FAQ

IS RED LENTIL SOUP GOOD FOR YOU?

Yes, red lentil soup is highly nutritious. Lentils are a good source of protein and fiber, and red lentil soup is packed with nutritious ingredients.

DO DRIED RED LENTILS NEED TO BE SOAKED?

No, dried lentils do not need to be soaked.

SHOULD YOU WASH RED LENTILS BEFORE COOKING?

Lentils do not need to be soaked, but it’s a good idea to rinse them under cool water before use because they are stored in large drums and can sometimes accumulate dust or debris. In modern times, lentils that make it to your kitchen will almost always be clean and ready to use, so it’s ok if you forget to rinse them.

WHAT LENTILS GO IN LENTIL SOUP?

You can use any lentils in lentil soup. Different types of lentils have different cooking times, so read the package instructions for the liquid-to-lentil ratio for the type of lentils you choose. The recipe on this page is best made with red lentils.